Methanol extracts of Callistemon viminalis (Sol. Ex Gaertner) G.Don Ex Loudon fruits, bark and leaves were tested for molluscicidal activity. Snails were collected and kept in dechlorinated water under standard condition. Ten adults B. Alexandrina, of the same size, were introduced in plastic acquaria for each experiment. The powdered organs extracted with methanol and the dried extracts were kept for testing as molluscicides. Different extracts proved to have molluscicidal activity against the vector of schistosomiasis, Biomphalaria alexandrina snails. LC50 values for C. viminalis fruits, bark and leaves were 6.2, 32 and 40 ppm respectively. The C. viminalis fruits extract showed the highest effect against the tested snails. Histopathological studies proved that the site of action of all tested extracts was localized in the digestive system and hermaphrodite gland.